Re: [Qemu-devel] virtio-net-pci possible limitation on AArch64

[Alexandru Avadanii]

Hi, Andrew,
Thank you for looking at this.
Comments inline.

> -----Original Message-----
> From: Andrew Jones [mailto:address@hidden
> Sent: Monday, July 24, 2017 6:02 PM
> To: Alexandru Avadanii
> Cc: address@hidden; svc-armband
> Subject: Re: [Qemu-devel] virtio-net-pci possible limitation on AArch64
> 
> On Fri, Jul 21, 2017 at 06:37:26PM +0000, Alexandru Avadanii wrote:
> > Hi,
> > I ran into an interesting limitation (or possibly bug) while trying to 
> > attach
> more than 3 (three) virtio-net-pci NICs to an AArch64 guest.
> > I created 4 network with virsh (see below for xml defitions) - nothing 
> > fancy,
> only 2 of them use NAT.
> >
> > Attaching a virtio-net-pci NIC for each network works well, VMs can be
> spawned, all devices are properly detected by the guest OS.
> > The first 3 guest interfaces work perfectly, however I can't get any traffic
> on the 4th one (in my case the public one).
> >
> > QEMU version: 2.9.0
> > Libvirt: tested with both 1.3.4 and 3.5.0, although I don't think
> > libvirt is to blame here
> 
> 1.3.4 is way too old for AArch64 guests - 3.0.0 was the first release that
> contained basic support. The XML below doesn't show what I'd expect for
> the PCIe topology either (see [*]), and that's likely the problem. I suggest
> you try a fresh VM creation using latest libvirt and virt tools.
> If it still doesn't work, then confirm it's not a bridging issue by checking 
> that
> it's always the forth network by changing their order.

I also tried libvirt 3.5.0, but maybe I missed something, like newer 
virt-tools. I will redo the test.
In my previous tests, I tried changing the order, and it was always the fourth 
interface having issues.

> 
> [*] QEMU doc: docs/config/mach-virt-graphical.cfg
> 
> > Host OS: Ubuntu Xenial 16.04.2 LTS
> > Guest OS: Ubuntu Xenial Cloud Image (latest available) Reproducibility
> > rate: 100% with below config
> >
> > VM is created with (also domain XML attached at the end of this mail):
> > $ virt-install --name cfg01 --ram 4096 --vcpus 6 --cpu
> > host-passthrough --accelerate \ --network
> > network:pxe,model=virtio-net-pci \ --network
> > network:mgmt,model=virtio-net-pci \ --network
> > network:internal,model=virtio-net-pci \ --network
> > network:public,model=virtio-net-pci \ --console pty --autostart
> > --noreboot --noautoconsole --video=vga --noautoconsole [...]
> >
> > You might notice I had to disable legacy virtio in the domain XML, or the
> guest would complain about a missing F_... property and no guest network
> interfaces would be detected.
> 
> You shouldn't need to do this disable-legacy stuff when using PCIe ports, as
> the virtio devices will automatically use virtio-1.0 ("modern").
> 
> >
> > For now, since we only need 4 guest interfaces, we switched one of them
> back to virtio-mmio, and everything is working as expected.
> > Unfortunately I can't investigate this myself right now, but I can provide
> additional details if needed for someone else to look into it.
> 
> I just checked on my setup (RH qemu based on 2.9, RH libvirt based on 3.2). I
> used Fedora 26's virt-manager from my x86 notebook, remotely connecting
> to my AArch64 host, in order to create four networks and a guest that has
> them all attached to four virtio nics. It worked without a hitch.

Good to know this is specific to my setup, I was afraid this is a real issue.
I'll retest using all suggestions above and get back with the rootcause.

Thank you,
Alex

> 
> Thanks,
> drew
> 
> >
> > BR,
> > Alex
> >
> > ---
> > Network definitions:
> > ---
> > <network>
> >   <name>pxe</name>
> >   <forward mode='nat'/>
> >   <bridge name='pxe' stp='on' delay='0'/>
> >   <ip address='192.168.10.1' netmask='255.255.255.0'>
> >     <dhcp>
> >       <range start='192.168.10.100' end='192.168.10.254'/>
> >     </dhcp>
> >   </ip>
> > </network>
> >
> > <network>
> >   <name>mgmt</name>
> >   <bridge name='mgmt' stp='on' delay='0'/>
> >   <ip address='172.16.10.1' netmask='255.255.255.0'>
> >   </ip>
> > </network>
> >
> > <network>
> >   <name>internal</name>
> >   <bridge name='internal' stp='on' delay='0'/> </network>
> >
> > <network>
> >   <name>public</name>
> >   <forward mode='nat'/>
> >   <bridge name='public' stp='on' delay='0'/>
> >   <ip address='10.16.0.1' netmask='255.255.255.0'>
> >   </ip>
> > </network>
> >
> > ---
> > Domain XML:
> > ---
> > <domain type='kvm' id='28'
> xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>
> >   <name>cfg01</name>
> >   <uuid>3f8415d1-963a-46aa-8a63-1c6558775b92</uuid>
> >   <memory unit='KiB'>4194304</memory>
> >   <currentMemory unit='KiB'>4194304</currentMemory>
> >   <vcpu placement='static'>6</vcpu>
> >   <resource>
> >     <partition>/machine</partition>
> >   </resource>
> >   <os>
> >     <type arch='aarch64' machine='virt-2.9'>hvm</type>
> >     <loader readonly='yes'
> type='pflash'>/usr/share/AAVMF/AAVMF_CODE.fd</loader>
> >     <nvram>/var/lib/libvirt/qemu/nvram/cfg01_VARS.fd</nvram>
> >     <boot dev='hd'/>
> >   </os>
> >   <features>
> >     <acpi/>
> >     <gic version='3'/>
> >   </features>
> >   <cpu mode='host-passthrough' check='none'/>
> >   <clock offset='utc'/>
> >   <on_poweroff>destroy</on_poweroff>
> >   <on_reboot>restart</on_reboot>
> >   <on_crash>restart</on_crash>
> >   <devices>
> >     <emulator>/usr/bin/kvm</emulator>
> >     <disk type='file' device='disk'>
> >       <driver name='qemu' type='qcow2' cache='none' io='native'/>
> >       <source
> file='/home/jenkins/alav/armband/upstream/fuel/mcp/scripts/images/mcp
> _cfg01.qcow2'/>
> >       <backingStore/>
> >       <target dev='vda' bus='virtio'/>
> >       <alias name='virtio-disk0'/>
> >       <address type='pci' domain='0x0000' bus='0x04' slot='0x00'
> function='0x0'/>
> >     </disk>
> >     <disk type='file' device='cdrom'>
> >       <driver name='qemu' type='raw'/>
> >       <source
> file='/home/jenkins/alav/armband/upstream/fuel/mcp/scripts/images/mcp
> _cfg01.iso'/>
> >       <backingStore/>
> >       <target dev='sda' bus='scsi'/>
> >       <readonly/>
> >       <alias name='scsi0-0-0-0'/>
> >       <address type='drive' controller='0' bus='0' target='0' unit='0'/>
> >     </disk>
> >     <controller type='scsi' index='0' model='virtio-scsi'>
> >       <alias name='scsi0'/>
> >       <address type='pci' domain='0x0000' bus='0x03' slot='0x00'
> function='0x0'/>
> >     </controller>
> >     <controller type='pci' index='0' model='pcie-root'>
> >       <alias name='pcie.0'/>
> >     </controller>
> >     <controller type='pci' index='1' model='dmi-to-pci-bridge'>
> >       <model name='i82801b11-bridge'/>
> >       <alias name='pci.1'/>
> >       <address type='pci' domain='0x0000' bus='0x00' slot='0x01'
> function='0x0'/>
> >     </controller>
> >     <controller type='pci' index='2' model='pci-bridge'>
> >       <model name='pci-bridge'/>
> >       <target chassisNr='2'/>
> >       <alias name='pci.2'/>
> >       <address type='pci' domain='0x0000' bus='0x01' slot='0x00'
> function='0x0'/>
> >     </controller>
> >     <controller type='pci' index='3' model='pcie-root-port'>
> >       <model name='pcie-root-port'/>
> >       <target chassis='3' port='0x10'/>
> >       <alias name='pci.3'/>
> >       <address type='pci' domain='0x0000' bus='0x00' slot='0x02'
> function='0x0' multifunction='on'/>
> >     </controller>
> >     <controller type='pci' index='4' model='pcie-root-port'>
> >       <model name='pcie-root-port'/>
> >       <target chassis='4' port='0x11'/>
> >       <alias name='pci.4'/>
> >       <address type='pci' domain='0x0000' bus='0x00' slot='0x02'
> function='0x1'/>
> >     </controller>
> >     <controller type='pci' index='5' model='pcie-root-port'>
> >       <model name='pcie-root-port'/>
> >       <target chassis='5' port='0x12'/>
> >       <alias name='pci.5'/>
> >       <address type='pci' domain='0x0000' bus='0x00' slot='0x02'
> function='0x2'/>
> >     </controller>
> >     <interface type='network'>
> >       <mac address='52:54:00:ae:48:81'/>
> >       <source network='pxe' bridge='pxe'/>
> >       <target dev='vnet0'/>
> >       <model type='virtio-net-pci'/>
> >       <alias name='net0'/>
> >       <address type='pci' domain='0x0000' bus='0x02' slot='0x01'
> function='0x0'/>
> >     </interface>
> >     <interface type='network'>
> >       <mac address='52:54:00:36:2c:a9'/>
> >       <source network='mgmt' bridge='mgmt'/>
> >       <target dev='vnet1'/>
> >       <model type='virtio-net-pci'/>
> >       <alias name='net1'/>
> >       <address type='pci' domain='0x0000' bus='0x02' slot='0x02'
> function='0x0'/>
> >     </interface>
> >     <interface type='network'>
> >       <mac address='52:54:00:43:ce:03'/>
> >       <source network='internal' bridge='internal'/>
> >       <target dev='vnet2'/>
> >       <model type='virtio-net-pci'/>
> >       <alias name='net2'/>
> >       <address type='pci' domain='0x0000' bus='0x02' slot='0x03'
> function='0x0'/>
> >     </interface>
> >     <interface type='network'>
> >       <mac address='52:54:00:37:e6:0e'/>
> >       <source network='public' bridge='public'/>
> >       <target dev='vnet3'/>
> >       <model type='virtio-net-pci'/>
> >       <alias name='net3'/>
> >       <address type='pci' domain='0x0000' bus='0x02' slot='0x04'
> function='0x0'/>
> >     </interface>
> >     <serial type='pty'>
> >       <source path='/dev/pts/0'/>
> >       <target port='0'/>
> >       <alias name='serial0'/>
> >     </serial>
> >     <console type='pty' tty='/dev/pts/0'>
> >       <source path='/dev/pts/0'/>
> >       <target type='serial' port='0'/>
> >       <alias name='serial0'/>
> >     </console>
> >     <graphics type='vnc' port='5900' autoport='yes' listen='127.0.0.1'>
> >       <listen type='address' address='127.0.0.1'/>
> >     </graphics>
> >     <video>
> >       <model type='vga' vram='16384' heads='1' primary='yes'/>
> >       <alias name='video0'/>
> >       <address type='pci' domain='0x0000' bus='0x02' slot='0x05'
> function='0x0'/>
> >     </video>
> >   </devices>
> >   <seclabel type='dynamic' model='apparmor' relabel='yes'>
> >     <label>libvirt-3f8415d1-963a-46aa-8a63-1c6558775b92</label>
> >     <imagelabel>libvirt-3f8415d1-963a-46aa-8a63-
> 1c6558775b92</imagelabel>
> >   </seclabel>
> >   <seclabel type='dynamic' model='dac' relabel='yes'>
> >     <label>+113:+115</label>
> >     <imagelabel>+113:+115</imagelabel>
> >   </seclabel>
> >   <qemu:commandline>
> >     <qemu:arg value='-global'/>
> >     <qemu:arg value='virtio-pci.disable-legacy=on'/>
> >   </qemu:commandline>
> > </domain>
> >